This invention relates generally to a mount for a disc-type switch and, specifically, to a mount for a flame rollout switch of the type used in a gas fired furnace to shut down the furnace in the event an over-temperature condition is sensed.
In many gas fired furnaces, a temperature sensitive disc-type flame rollout switch is employed to detect when the furnace flue system or combustion air supply becomes clogged to a point wherein a flame rollout could pose a dangerous situation. The flame rollout switch is mounted upon the furnace in a location where flames might occur in the event that the flue system or the combustion air supply becomes blocked. This, in turn, causes a rise in the switch temperature which opens the switch thereby shutting down the furnace.
Disc type switches are generally supplied by the various manufacturers with a mounting flange that surrounds the body of the switch. In order to minimize the costs, the switch flange is usually fabricated of a thin metal plate that can be easily deformed or bent. A hole is generally provided in the substrate upon which the switch is located so that the body of the switch can pass into or through the substrate thus placing the mounting flange in seating contact against the top surface of the substrate. In some applications, screws are used to secure the flange to the substrate. In other applications, the toe end of the flange is captured in a pocket and the opposite end of the flange is secured to the substrate using a single screw.
Lead connectors are used to couple the electrical lead to the switch terminals. To ensure the reliability of the connection, the connectors must meet certain industry standards involving the amount of force required to unplug the connector from the terminal. This pull-out force is high enough to damage the mounting flange and thus require replacement of the switch.
It is a primary object of the present invention to improve apparatus for mounting disc-type switches upon a flat substrate.
It is a further object of the present invention to protect a disc-type switch from damage during periods of maintenance or the like requiring the removal of the lead connectors from the switch terminals.
A still further object of the present invention is to provide an improved mounting arrangement for a disc-type switch.
Another object of the present invention is to more securely support the mounting flange of a disc-type switch in assembly.
These and other objects of the present invention are attained by apparatus for securing a disc-type switch to a substrate. Typically, the switch has a body that is centered in a flange having a first half section that is symmetrical with a second half section. The switch body extends upwardly from the top surface of the flange and downwardly from the bottom surface of the flange. The substrate contains a hole for receiving the body of the switch and a slot that is aligned along a reference line that passes through the center of the hole and which extends to either side of the hole a sufficient distance to permit the flange to be passed through the substrate. A depression is formed in the substrate on one side of the reference line that is capable of housing one half section of the flange. In assembly, the switch body and the flange are passed through the substrate and turned to bring the one half section into the depression and the other half section into seating contact against the top surface of the substrate. A fastener is used to secure the other half section to the substrate thus locking the switch to the substrate.